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What is the nickname for Vitamin B3? What is it's active form?
NAD+ and NADP+
What is the function of Vitamin B3/Niacin?
Conenzymes for oxidoreductase, enzymes involved in carbohyrdate/amino acid/lipid metabolism
What are the dietary sources for Vitamin B3/niacin?
Whole grain, enriched cereal, meat, milk
60 mg tryptophan converted to 1 mg eq niacin
Vitamin B3 deficiency leads to __________, which is characterized by the four D's: ____, _____, _____, _____
Diarrhea, dementia, dermatitis, death
The clinical implications of Vitamin B3 are ______
Hypercholesterolemia: lowers plasma cholesterol and TAG by inhibiting FFA release from adipose tissue (Aka lipolysis). Doses of 1.5 g/day or 100 x the RDA
CI: arterial bleeding, ulcer, may cause hyperglycemia in DM pts
Toxicity: liver damage at
What is the nickname for Vitamin B5? What is it's activated form?
CoA and ACP (Acyl carrier protein)
What is the function of Vit B5/pantothenic acid?
Acyl transfer in CAC, FAS, oxidation, cholesterol synthesis, acetylation reaction.
The thiol group carries the acyl radicals
What are the dietary sources of Vit B5/pantothenic acid? Are deficiencies rare or common?
Vit B5 is found everyone!
Deficiencies are rare
What is the nickname for Vitamin B7? What is it's active form?
Biotin is in active form!
What is the function of Vitamin B7/Biotin?
Biotin bound to the E-amino group of a lysine residue of biotin-dependent enzymes
What are the sources for Vitamin B7/biotin?
It is synthesized by intestinal bacteria, and also widespread: liver, milk, egg yolk
How is a vitamin B7/biotin deficiency caused?
Consumption of raw egg:
egg white contains avidin, which binds tightly to biotin and is heat labile. (this requires 20-30 raw eggs/day or maybe 2-3 raw eggs/day x 3 mo)
What is the nickname for Vitamin B9? What is it's active form?
Active form is tetrahydrofolate (THF)
What is the function of Vitamin B9/THF?
One carbon carrier
Methionine and cystein metabolism, DNA synthesis
What are the sources of Vitamin B9/THF?
Leafy greens- lasts in body about 4 mo
How does a vitamin B9/THF deficiency occur? What does it result in?
Occurs as a result of increased demands (pregnancy), poor absorption (diseased SI, alcoholism, drugs such as methotrexate), genetic disorder
Results in megaloblastic anemia, neural tube defects
What is megaloblastic anemia?
Characterized as normochromatic and macrocytic (larger RBC than normal)
How is megaloblastic anemia caused?
Failure to synthesize adequate amount of DNA due to folate and/or vitamin B12 deficiency
Folate is necessary for dTMP synthesis and B12 is required for folate activation.
This results in the RBC being stuck in the S phase of the cell cycle
What is a neural tube defect and how is it caused?
Results in anencephaly and spina bifida
Caused by folate deficiency during pregnancy
Preventable with folate substances (at least 400 ug/day)
In order to prevent neural tube defects in pregnancy, ____________________
adequate folate must be present during the time of contraception (first week)
Regulation of homocysteine is controlled by __________
Vitamin B6, B12, folate
High homocysteine level is associated with _____________
higher risk of cardiovascular disease
Vitamin B12 has ______ in the center
What is the nickname for Vitamin B12?
Cobalt containing corrin/prophyrin complex molecule
Vitamin B12 is synthesized only by _______ and it's dietary sources is _______. _________ are at risk for deficiency
IF is a protein produced by the _______ that is necessary for __________
absorption of Vitamin B12
Vitamin B12 is transported via the carrier protein ________
Vitamin B12 bound to _______ in the serum is prevented from being _______
Unlike other water soluble vitamins, ______ can be stored in the body for several months
What is the function of Vitamin B12/THF?
Methionine synthesis, folate metabolism, control of homocysteine level, DNA synthesis, formation of odd number carbon atoms (isomerization of methylmalonyl CoA)
A vitamin B12 deficiency is most likely to affect _________
rapidly dividing cells
What is the Methyl-folate trap
Without B12 to accept methyl group from 5-methyl THF, 5-methyl THF accumulates and is trapped and THF is not regenerated
Vitamin B12 is necessary for ________ activation
Pernicious anemia is an ________ disease that destroys the ____________, resulting in the reduction of ____
parietal cells in the stomach
Pernicious anemia is characterized by _____ anemia resulting from ________
impaired DNA synthesis
Pernicious anemia has ___________ dysfunction, due to ______. These symptoms may occur ______
demyelination in peripheral nerves and the spinal cord
in the absence of anemia
Vitamin B6's nickname is ___________ and it's active form is ________
Pyridoxine, pyridoxal, pyridoxamine and their phosphate derivatives.
Active form: PLP
What is the function of Vitamin B6?
Amino acid metabolism (transamination/deamination)
Conversion of tryptophan to Niacin
Synthesis of neurotransmitters (serotonin, melatonin, dopamine, NE, GABA)
RBC formation and function
What is the main difference between the symptoms of Vit B1 deficiency and Vit B6 deficiency?
Vit B6 deficiency does not lead to ANY eye movement problems, while B1 does
What are the dietary sources of Vitamin B6?
Liver, fish, meat, wheat, corns, eggs, nuts, legumes
If you have higher intake of protein, then your requirement for Vit ___ is _______
Deficiencies of Vitamin B6
Most common in alcoholics with general vitamin B deficiency (peripheral neuropathy, sideroblastic anemia, seizues)
Caused by isoniazid drug usage, which depletes Vitamin B6
There is potential toxicity with high dose of _______
What is vitamin C's nickname?
How is vitamin C synthesized?
Synthesis from glucose in some organisms, not in humans or guinea pigs
What are the functions of Vitamin C?
Collagen synthesis (hydroxylation of lys & pro)
Tyrosine degradation, reducing Cu and Fe
Epinephrine synthesis from tyrosine
Bile acid formation
Vitamin C is a major water soluble _______
Vitamin C is easily destroyed by ______________
oxygen, metal, high pH, heat and light
What are the dietary sources of Vit C?
Citrus fruits and potatoes
What are some of the characteristics of scurvy?
corkscrew hair, ginival hemorrhage
dry mouth/eyes, peeling gum, loose teeth, fragile blood vessels, joint/leg pain
Lipid soluble substances can be stored in the ______
B-carotene can give rise to ________
two molecules of retinal
The biologically active form of Vitamin A is _______
What are the dietary sources of vitamin A?
Animal origin: liver milk, vitamin A fatty acid ester
Plant origin: red/orange/yellow fruits and dark green veggies, pro-vitamin A carotenoid (includes B-carotene)
Describe the metabolism of Vitamin A - Step 1a
Ingested retinol esters hydrolyzed in the intestinal mucosa, releasing retinol and FFA
Retinol is then absorbed into the enterocytes and esterified to fatty acid and incorporated to chylomicrons.
Distribution from the liver to other tissues via r
Describe the metabolism of Vitamin A - Step 1b
Ingested beta-carotene cleaved in the intestinal lumen by b-carotene dioxygenase, yielding retinal
RETINAL is reduced to RETINOL by retinaldehyde reductase within the lumen
Retinol is then absorbed into the enterocytes and esterified to fatty aci
______ is required in the retina and reproductive system
retinoic acid is required in ________
What causes deficiency of Vitamin A?
Reduced dietary sources: malnutrition, alcoholism, fat absorption and storage problems
Reduced RBP synthesis - liver dysfunction and other nutrient deficiencies such as Zinc
What are the cellular functions of Vitamin A?
Epithelial cell maintenance and differentiation
Antioxidant -- ESPECIALLY B-carotine
rhodopsin consists of _____ and ______
opsin and retinal
Each photoreceptor cell contains stacks of discs in the ______
11-cis retinal is activated and _____________, when light hits rhoposin, it becomes ___________
fits into a compact rhodopsin molecule
isomerized no longer fits into the binding site
Vitamin A deficiency in the eye is a leading cuase of ____________
leading cause of blindness in children worldwide
An early symptom of Vitamin A deficiency is ___________
What is xerophthalmia characterized by?
Night blindness is caused by decreased level of _______ for the visual cycle. This leads to poor __________ of the rods. This
vitamin A supplementation
Conjunctival xerosis results from damage to _________ and the proliferation of ___________
basal epithelial cells
Bitot's spots are _________
keratinized epithelial debris
Early symptom of corneal serosis is _______
If left untreated, corneal xerosis leads to ________
epithelial defects, stromal efema, keratinization of the epithelium
Ulceration of the cornea, leading to a higher risk for bacterial infection
Vitamin A toxicity results in ______________
Bone demineralization, bone pain, hair loss, dermatitis, rash, hepatosplenomegaly, nausea, vomiting, double vision, headaches, and diarrhea
Headache, idiopathic intracranial hypertension, dry eyes, carotenoderma
Vitamin A supplement intake is the most likely cause of ______
vitamin a toxicity
Vitamin A toxicity is acute if greater than __________ and chronic if greater than ______
Increased consumption of B-cerotene is associated with reduced risk of ______
macular degeneration, cataracts and cardiovascular diseases
Normal epithelial cell growth and differentiation requires ______
Insufficient zinc levels _____ vitamin A metabolism by ______
decreasing the RBP synthesis, decreasing the mobilization of retinol from the liver (reduced activity of the enzyme converting storage form to retinol), decreasing the conversion of retinol to retinal
Clinical uses of Vitamin A include: _______
Trans-retinoic acids and 12-cis-retinoic acid for ACNE TREATMENT
Etretinate and tazarotene (2nd and 3rd generation reinoid) for PSORIASIS TREATMENT
Sources of Vitamin D
Diet: ergocalciferol and cholecalciferol
Endogenous: cholesterol converted to D3 via UV rays in the skin
Vitamin D 25-OH D3 vs 1,25-(OH)2 D3
Vitamin D 25-OH D3: formed in the liver
1,25-(OH)2 D3: formed in the kidney (and bone); the most potent form
The most potent form of Vitamin D
1,25-(OH)2 D3 (formed in the kidney and bone)
What is the function of Vitamin D?
In high plasma calcium levels: there is increased bone mineralization
In low plasma calcium levels: there is increased calcium absorption in the intestine, stimulating reabsorption of calcium by the kidney, increasing bone demine
Vitamin D deficiency leads to _______
soft bone, rickets, osteomalacia
Vitamin D deficiency leads to ______
cancers, infectious disease, type II diabetes, heart diseases, stroke, other inflammatory diseases
Autoimmune diseases: type I diabetes, MS, Crohn's disease, rheumatoid arthritis
Alzheimer's, dementia, depression, schizophrenia
Vitamin D toxicity
Deposition of calcium in many organs, including the arteries and kidneys
Vitamin E four forms
Four forms in nature: alpha, beta, gamma, delta - tocopherols
The most active form of vitamin ___ is most active and efficient antioxidant in the blood and tissues
Vitamin E ALPHA
Vitamin E functions
Antioxidant for peroxidation of PUFA in the membrane
Most efficient order higher oxygen partial pressure in the RBC, lung and retina
Vitamin E essential for protecting _______ from _____
PUFA (poly unsaturated fatty acids) from peroxidation
What are the sources of Vitamin E?
Vegetable oils and nuts
Vitamin E deficiency results in ______
Anemia due to low hemoglobin production and decreased RBC life span.
Restricted to premature infants; dysfunctional lipid metabolism in adults
Vitamin ____ is the least toxic among fat-soluble vitamins
A CI of Vitamin E is _______
iron deficient anemia, vitamin K deficiency or blood thinner use
Vitamin K is required for __________ and _______ by a Vitamin K dependent carboxylase
blood factor synthesis and osteocalcin (bone protein)
What are the dietary sources for Vitamin K?
Widely distributed, intestinal bacteria, green leafy veggies
Vitamin K deficiency can be caused by __________ usage, and disease affecting __________ in newborns
long term antibiotic
What is the toxicity of vitamin K?
reported only with menadione: hemolytic anemia, jaundice
Warfarin is a __________ antagonist by _______
blocking the regeneration of Vit K in the Vit K cycle
Carotenoids are _____, ______, and ______ pigments synthesized by _______
yellow, orange, and red
Which carotenoids are provitamin A ___________, ________, _________
alpha-carotene, beta-carotene and beta-cryptoxanthin
Which carotenoids have no vitamin A properties? (3)
Carotenoid Metabolism follows the ________ absorption route. Provitamin A to vitamin A occurs in the ________ and ________ an
liver and small intesetine
vitamin A toxicity
Vitamin A has antioxidant activity in ____ but unclear in ______
Association between beta carotene and lung cancer risk
beta carotene increased risk in smokers and decreased risk for non smokers.
There is an overall _______ risk of prostate cancer with higher lycopene intake
What is lycopenodermia? what is it a symptom of?
dark orange skin; lycopene toxicity
L, Z, and MZ have a _______ backbone that is ________. They function to absorb ____________, _______, provide __________. L
blue light in the retina
L and Z is absorbed from the diet while MZ is derived from L in the central macula
Functions of MP
Absorption of blue light
Rigidity in the membrane
Minimization of chromatic aberration
_______ are tightly bound to proteins in the foot matrix or solubilized in some lipids
L and Z
____ is dominant in diets
_____ Z is only found in the retina, but not the plasma
L and Z are transported to neuronal tissues via _____
L and Z are found in all ocular structures, except the __________. They are highly concentrated in the retina (___ mM) compar
vitreous, sclera and cornea
1 mM compared to 1 uM
XBP (Xanthophyll binding protein) for Z
MZ is _____ and only present in the _______. Z is predominant in the _______. L is predominant in the _______
endogenous, central macula
parafovea and periphery
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